HHE support

Chocolate Heretic includes support for HHE patches, which are the Heretic equivalent of dehacked patches.

As far as is known, Chocolate Heretic is the first source port to support loading of HHE patches. HHE support is significantly more difficult to implement than dehacked support, as the HHE patch format has a strong dependency on the DOS Heretic executables. Some patches will work only with one particular version of Heretic, and will not work with others. Chocolate Heretic aims to support patches created for all three Heretic versions (v1.0, v1.2, v1.3). A command line option, -hhever allows the version to emulate to be specified.